In order to be effective in cleaning the teeth, dentifrices must contain a polishing agent or an abrasive ingredient such as calcium carbonate, dicalcium phosphate, tricalcium phosphate, calcium pyrophosphate, sodium metaphosphate, hydrate silica and the like. Some stains, particularly coffee and tea stains, tenaciously adhere to the tooth surfaces and are, therefore, much more difficult to remove. While a more abrasive polishing agent can be used, those generally result in damage to the oral hard tissues after prolonged use of the dentifrice.
It has now been found that a dentifrice containing an appropriate amount of a particular abrasive system, namely a combination of anhydrous aluminum silicate and diatomaceous earth (silica), can be used to provide a high polishing, high cleaning dentifrice which is not overly abrasive (radioactive dentin abrasion index in the 130-150 range). Other abrasive agents can also be present, if desired.
Dentifrices containing diatomaceous silica are known. Thus, U.S. Pat. No. 2,820,000 describes a dentifrice containing primarily diatomaceous earth (silica). However, this abrasive alone does not provide a high polishing and high cleaning formulation which is not overly abrasive.
U.S. Pat. Nos. 3,906,090 and 4,364,579 teach dentifrices containing interbonded silicates and alumina, for example sodium aluminosilicate complex, as abrasives. These interbonded silicates and alumina are chemically different from the anhydrous aluminum silicate and diatomaceous earth (silica) of the present invention and none of the silicates or alumina, being mildly abrasive, are very effective cleaning agents. The combination of the anhydrous aluminum silicate with diatomaceous earth (silica) provides a high polishing and cleansing dentifrice with superior cleaning capabilities to that provided by using either of these polishing agents alone. The combination also provides superior cleaning efficacy compared to the leading commercial family toothpaste (which contains a milder abrasive system) but the combination is not so abrasive so as to damage the oral tissues. The combination also provides superior cleaning efficacy compared to a commercial dentifrice which is specifically promoted for removal of tobacco stains.
It is accordingly the object of this invention to provide a new dentifrice which has high polishing and cleaning properties suitable for removal of tenacious stains on teeth, such as coffee and tea stains, yet not be too abrasive so as to damage the oral tissues with daily use. This and other objects of the invention will become apparent to those skilled in the art from the following detailed description.